Helmet



FIG. 1 is a perspective view of a helmet showing our new design;

FIG. 2 is a side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear veiw thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines in FIG. 5 are for illustrative purposes only and form no part of the claimed design. The straps shown in FIGS. 1-3 and 6 are shown broken away and are understood to represent indeterminate length. 

The ornamental design for a helmet, as shown and described. 